by main force
 竭盡全力地,全力以赴地
 Main a.
 1. Very or extremely strong. [Obs.]
    That current with main fury ran.   --Daniel.
 2. Vast; huge. [Obs.] “The main abyss.”
 3. Unqualified; absolute; entire; sheer. [Obs.] “It's a man untruth.” --Sir W. Scott.
 4. Principal; chief; first in size, rank, importance, etc.; as, the main reason to go; the main proponent.
    Our main interest is to be happy as we can.   --Tillotson.
 5. Important; necessary. [Obs.]
 That which thou aright
 Believest so main to our success, I bring.   --Milton.
 By main force, by mere force or sheer force; by violent effort; as, to subdue insurrection by main force.
    That Maine which by main force Warwick did win.   --Shak.
 -- By main strength, by sheer strength; as, to lift a heavy weight by main strength.
 Main beam Steam Engine, working beam.
 Main boom Naut., the boom which extends the foot of the mainsail in a fore and aft vessel.
 Main brace. (a) Mech. The brace which resists the chief strain.  Cf. Counter brace. (b) Naut. The brace attached to the main yard.
 Main center Steam Engine, a shaft upon which a working beam or side lever swings.
 Main chance. See under Chance.
 Main couple Arch., the principal truss in a roof.
 Main deck Naut., the deck next below the spar deck; the principal deck.
 Main keel Naut., the principal or true keel of a vessel, as distinguished from the false keel.
 Syn: -- Principal; chief; leading; cardinal; capital.